questionnaire survey on the use of in-vitro bioaccessibility in human … · 2014. 3. 13. ·...

Questionnaire survey on the use ofIn-vitro bioaccessibility in humanhealth risk assessment

Science Report: SC040060/SR1

SCHO0906BLLW-E-P

Science project SC040060 - Questionnaire survey on the use of In-vitro bioaccessibility in humanhealth risk assessment 2

The Environment Agency is the leading public body protecting andimproving the environment in England and Wales.

It’s our job to make sure that air, land and water are looked after byeveryone in today’s society, so that tomorrow’s generations inherit acleaner, healthier world.

Our work includes tackling flooding and pollution incidents, reducingindustry’s impacts on the environment, cleaning up rivers, coastalwaters and contaminated land, and improving wildlife habitats.

This report is the result of research commissioned and funded by theEnvironment Agency’s Science Programme.

Published by:Environment Agency, Rio House, Waterside Drive,Aztec West,Almondsbury, Bristol, BS32 4UDTel: 01454 624400 Fax: 01454 624409www.environment-agency.gov.uk

ISBN: 1844325970

© Environment Agency September 2006

All rights reserved. This document may bereproduced with prior permission of theEnvironment Agency.

The views expressed in this document are notnecessarily those of the Environment Agency.

This report is printed on Cyclus Print, a 100%recycled stock, which is 100% post consumer wasteand is totally chlorine free. Water used is treatedand in most cases returned to source in bettercondition than removed.

Further copies of this report are available from:The Environment Agency’s National CustomerContact Centre by [email protected] by telephoning 08708 506506.

Author(s):Bob Barnes, Albania Grosso, Sohel Saikat,David Westwood

Dissemination Status:Publicly available

Keywords:Land Contamination, Bioaccessibility,Risk Assessment, Questionnaire

Research Contractor:Entec UK LtdCanon Court,Abbey Lawn, Abbey ForegateShrewsburySY2 5DETel: 01743 342000

Environment Agency’s Project Manager:Bob Barnes, Olton Court

Collaborators:All the local authorities that kindlyparticipated in the Survey

Science Project Number:SC040060

Product Code: SCHO0906BLLW-E-P


Science at the Environment Agency

Science underpins the work of the Environment Agency, by providing an up to dateunderstanding of the world about us, and helping us to develop monitoring tools andtechniques to manage our environment as efficiently as possible.

The work of the Science Group is a key ingredient in the partnership between research,policy and operations that enables the Agency to protect and restore our environment.

The Environment Agency’s Science Group focuses on five main areas of activity:

• Setting the agenda: To identify the strategic science needs of the Agency to informits advisory and regulatory roles.

• Sponsoring science: To fund people and projects in response to the needsidentified by the agenda setting.

• Managing science: To ensure that each project we fund is fit for purpose and that itis executed according to international scientific standards.

• Carrying out science: To undertake the research itself, by those best placed to do it- either by in-house Agency scientists, or by contracting it out to universities, researchinstitutes or consultancies.

• Providing advice: To ensure that the knowledge, tools and techniques generated bythe science programme are taken up by relevant decision-makers, policy makers andoperational staff.

Steve Killeen Head of Science


Executive SummaryThis report details the results of a questionnaire survey undertaken by the EnvironmentAgency on local authority officers in England and Wales. The survey was designed toobtain information on bioaccessibility testing of metals in soils, specifically:

The perceived extent and types of metal soil contamination. The uptake of bioaccessibility tests in England and Wales. The local authorities views on the acceptability of data from bioaccessibility tests in

human health risk assessments.

The Environment Agency received responses from approximately a quarter of theauthorities and the survey revealed a number of important findings.

Ninety per cent of participants reported having sites with high levels of heavy metalsin their areas.

The overwhelming majority of participants indicated arsenic as the main metalcontaminant of concern, followed by lead, nickel and cadmium.

The source of this metal contamination was attributed equally to natural backgroundsources and anthropogenic activities.

Of the participants in this survey, half of them had received bioaccessibility dataand/or estimates as part of their regulatory duties with respect to land contamination.All the participants that had received such data had received it for arsenic, whilearound a quarter of participants had received bioaccessibility data for lead and nickel.

Of those that had received bioaccessibility data, 85.7 per cent had at some timeaccepted it when provided as part of risk assessments. Arsenic was the maincontaminant for which participants accepted bioaccessibility data.

Those rejecting bioaccessibility data did so either on the basis of a lack of centralisedguidance on its use or due to poor use of the data within the risk assessments.

Most participants had only occasionally received measurements or estimates of oralbioaccessibility in the past two years, but about half reported that the use ofbioaccessibility testing was increasing.

The results have been used to inform the Science Group's programme on bioaccessibilitytesting.


ContentsGlossary and Acronyms - 6

1 Introduction - 8

2 Approach - 10

3 Results - 12

4 Discussion - 29

5 Summary - 31

References - 32

Appendix A - Questionnaire - 34

Appendix B - Results Summary - 40


Glossary and AcronymsAnthropogenicCaused by or relating to human activity

BGS British Geological Survey

Bioaccessibility Fraction of the contaminant that is released into solution from thesoil during digestion

Bioavailability Fraction of the dose of the contaminant that is absorbed by thebody

CI Confidence Interval

CLEA Contaminated Land Exposure Assessment

CLR Contaminated Land Report – a series of reports publishedoriginally by the Department of the Environment and latterly byDefra and the Environment Agency on the management of landcontamination

Defra Department for Environment, Food and Rural Affairs

FSA Food Standards Agency

GLM Generalised Linear Modelling

GIS Geographical Information System

HCV Health Criteria Value – a summary term for toxicology-basedcriteria representing a level of intake that pose a minimal risk tohuman health

HPA Health Protection Agency

ICRCL Interdepartmental Committee on the Redevelopment ofContaminated Land – it published soil standards that have sincebeen withdrawn and superseded by the SGVs

ID Index Dose

In vitro ‘In Glass’ – in this context an artificial, non-animal bioaccessibilitymodel/extraction and analytical procedure

In vivo ‘In Living’ – in this context a live animal bioavailability test

MCerts Environment Agency's Measurement Certification Scheme

ODPM Office of the Deputy Prime Minister

PBET Physiologically Based Extraction Test – an in-vitro bioaccessibilitytest


SGVs Soil Guideline Values

SNIFFER Scottish and Northern Irish Forum For Environmental Research

Special Site A Contaminated Land site defined under Part IIa of theEnvironmental Protection Act 1990 that is regulated by theEnvironment Agency

TDI Tolerable Daily Intake – the amount of a contaminant that can beingested into the human body below which there is little or no riskof harm to human health


1 IntroductionThe Environment Agency acts as an advisor to central Government on manyenvironmental issues, including the assessment of risks to health from landcontamination. As part of this role, the Environment Agency, in conjunction with theDepartment for Environment, Food and Rural Affairs (Defra), has published documentsthat provide guidance on conducting risk assessments for land contamination (Defra andthe Environment Agency 2002a, b and c). These documents include details on genericassessment criteria (also known as Soil Guideline Values (SGV)), which are based ongeneric assumptions made about soil types, soil pH, contaminant level and exposurescenario (Defra and the Environment Agency 2002d). An SGV is derived by comparingpredicted human exposure to a contaminant with a Health Criteria Value (HCV), whichdenotes the exposure below which there is thought to be little or minimal risk to humanhealth. The oral HCV for a contaminant can be derived from experiments using a numberof media (such as food and water), but it is unusual for HCVs to be derived on the basisof soil exposure.

Soils are, by nature, heterogeneous in their geo-physical and chemical properties, andthis is likely to affect the level of human exposure to contaminants and their mobilitywithin the human body. This variation in soil properties, combined with the differentmedia used in the derivation of the HCVs, mean that mechanisms of contaminant uptakethat have not been considered in producing an SGV may be important at some sites.This could result in risks to health at such sites being over- or underestimated. Thecurrent debate in Europe and North America is centred around the application ofbioavailability or, more commonly, bioaccessibility testing as a potential tool to refine therisk assessment of land contamination on a site-specific basis (Environment Agency2005 a,b, US EPA 2005).

The Environment Agency and the British Geological Survey (BGS) have collaborated ontwo research projects on bioaccessibility in the UK (Environment Agency and BGS 2002a,b). The first project reviewed and summarised currently available in vitro tests forevaluating the oral bioaccessibility of selected metals and metalloids (such as arsenic,lead, cadmium, and copper) in contaminated soils. The project report included a briefoutline of the methodologies used and a critical commentary on their robustness andvalidity for measuring bioaccessibility (Environment Agency and British GeologicalSurvey 2002a).

The second project concentrated on the measurement of arsenic oral bioaccessibility inUK soils using one of the in vitro tests reviewed in the first project. The test was used onsoils from three sites in the UK known to have elevated levels of arsenic. The results ofthe bioaccessibility tests from the soils tested varied by 0.5–45 per cent depending onthe soil tested. Given all the uncertainties identified by the study, the researchersrecommended that further research needed to be carried out to ensure that in vitro testdata relates to human bioavailability for a wider range of soil types and arsenicconcentrations (Environment Agency and British Geological Survey 2002b).

In February 2005, the Environment Agency published a science update on the use ofbioaccessibility testing in risk assessments of land contamination (Environment Agency2005a). The report concluded that, on the basis of the information currently available, theEnvironment Agency could not recommend the use of bioaccessibility testing at that time.It also stated that should practitioners make use of the techniques and submit them to


the Environment Agency for review, the data should be treated with caution andsupported by a significant body of evidence. This should indicate that the methods arescientifically robust, suitable for the site and the contaminants concerned, and that theuncertainties inherent in the methods are understood and have been taken into account.

Although the projects and reports detailed above identified all the uncertaintiesassociated with bioaccessibility testing, it was brought to the Environment Agency’sattention that these tests were being used in the UK (Environment Agency 2005b). Theprecise extent to which bioaccessibility tests were being used was not altogether clearand it was therefore deemed necessary to determine whether these tests were beingused routinely and what methods were being employed by the contract laboratoriesconducting the tests.

The following two projects were initiated to answer these questions.

A questionnaire survey – to determine the extent of use of bioaccessibility tests in theUK and the reasons for using them.

An inter-laboratory comparative study – to determine the tests/methods provided bythe contract laboratories and the intra- and inter-variability of the test results.

The purpose of the questionnaire was to illicit information on:

● the use of bioaccessibility tests in England and Wales;● and local authorities’ experiences and views on the acceptability of the results of

such tests in the risk management of land contamination.

The results of the questionnaire form part of the Environment Agency's scienceprogramme to inform any potential future policy in this area. This report presentsinformation on the approach adopted for conducting the survey, together with its findings.


2 ApproachThe lead regulators for land contamination are the local authorities, under both theplanning system (ODPM 2004) and the Contaminated Land Regulations (DETR 2000,WAG 2001). Under these regimes, the issues of assessing and mitigating risks and harmto human health fall to local authorities, except were land is designated as a 'special site'.In this case, the Environment Agency assumes the role of lead regulator. Given thissituation, a decision was taken to send the questionnaire to local authority contaminatedland officers (or their equivalent), since these officers were most likely to haveexperience in reviewing and assessing the results of bioaccessibility tests. In addition,the Environment Agency's area contaminated land officers were also contacted todetermine if they had any experience of using bioaccessibility tests.

There are 353 district and unitary local authorities in England and 22 unitary authorities inWales. Initially, it was intended only to target those local authorities within areas thoughtto have naturally-occurring elevated levels of arsenic (169 authorities). However,anecdotal information indicated that bioaccessibility tests were being carried out forcontaminants other than arsenic. Therefore, it was decided that all 375 districts andunitary local authorities in England and Wales would be contacted.

One of the assumptions of the survey was that arsenic is the predominant contaminantfor which bioaccessibility tests are used to assess human health risks in England andWales. The second assumption was that the response rate to the questionnaire would begreater for areas of England and Wales with elevated levels of arsenic contamination.The questionnaire was therefore designed, in part, to test these assumptions.

Given the large number of authorities that needed to be contacted, the questionnaire wassent to local authority officers in England and Wales who deal with land contaminationissues via e-mail. E-mail addresses were obtained from central Government.Unfortunately, given the number of local authorities in England and changes to personneland IT systems, that information was not completely up-to-date. Environment Agencyarea officers were requested to inform local authority officers within their areas of theproject and questionnaire, in order to help increase the survey coverage.

In March 2005, the questionnaire (see Appendix A) was e-mailed to 375 contaminatedland officers at local authorities in England and Wales. Recipients of the questionnairewere invited to respond either by email, fax, or post, in order to make submitting aresponse as easy as possible and thereby maximise the number of responses.

The questionnaire consisted of thirteen multiple-choice questions. Each question had aminimum of four possible choices and additional space for comment after each question.The fourteenth and final question allowed respondents to make comments on any issueassociated with bioaccessibility testing.

Questions 1–3 were designed to determine:• whether there were high concentrations of metals in the area;• what metals were perceived to be elevated;• and whether the source was natural or anthropogenic.

Questions 4–11 were designed to determine:• if regulatory decisions had been made in the local area on the basis of potentialhuman health risks from land contamination;• what contaminants were identified as the risk drivers;


• whether bioaccessibility test results were used in the assessment of risks;• and how the use of the results from bioaccessibility tests were justified.

The basis for questions 12 and 13 was to determine whether there is a perceivedincrease in the use of bioaccessibility tests and, if so, for what contaminants. The finalquestion was meant to capture anything that the local authorities wanted to report withregard to bioaccessibility testing.

Participants were requested to indicate all appropriate choices that were applicable totheir own particular circumstances for each of the questions. Therefore the number ofreplies to be collected could be greater than the total number of responses and the sumof percentage replies could exceed 100 per cent.

Once the completed questionnaires were received, they were transferred to aspreadsheet. This was set up to evaluate the rate of response to the questionnaire on thebasis of the Environment Agency’s eight regions and 26 areas. The responses werechecked for consistency and clarity. If an inconsistency was identified then the relevantlocal authority was contacted to clarify the issues. This was done using phone interviews,and the results incorporated into the spreadsheet containing all the responses. In a fewinstances it was not possible to contact a local authority officer to seek clarification oftheir answers and resolve inconsistencies. These instances are detailed within therelevant parts of Section 3 below.

The spreadsheet information was subsequently used to calculate information on theresponse rate for the survey and for analysing each question on the basis of theresponses.


3 ResultsOf the 375 district and unitary local authorities in England and Wales, 298 weresuccessfully contacted. Responses were received from 99 authorities, representing 33.2per cent of those contacted and 26.4 per cent of all local authorities. Of the localauthorities that responded, only one reported that they had difficulty in putting informationinto the electronic draft and returned the questionnaire partially completed.

Environment Agency staff indicated that they had not received bioaccessibility test datain the course of their work and they therefore had no influence on the survey. TheEnvironment Agency would only have a role in the assessment of health risks from landcontamination where it was the regulator of a special site.

The analysis of responses for each question is presented separately in the followingsections. Participants were requested to indicate all appropriate answers for eachquestion that were applicable to their authority. Basically, participants were encouragedto tick as many answers as applicable to each question. Hence the number of repliesoften exceeded the total number of participants that answered the question. Wherepercentage values are presented, these values represent the fraction (as a percentage)of the replies received relative to the total number of participants. This explains why thesum of percentage replies often exceeds 100 per cent. The number of responses is givendirectly below each question. Table B.2 provides details of the number of multipleanswers to each question.

A summary breakdown of responses, including the confidence interval for eachresponse, is presented in Appendix B. These confidence intervals should be taken intoaccount when analysing the results of this questionnaire. Ninety percent confidence limitsfor proportional response data were calculated using the binomial distribution. Theseconfidence limits were then modified with a finite population technique, as 26.4 per centof the total number of local authorities responded to the questionnaire survey. Theseconfidence limits for the responses are shown in Table B.1 and as error bars on Figure 3.

Table 1 illustrates the questionnaire response rates grouped into the EnvironmentAgency’s eight regions and 26 areas. The fifth column of Table 1 – headed ‘Percentage ofArea > SGV’ – indicates the approximate percentage area within the Environment Agency’sregions and areas that may potentially exceed the arsenic SGV for the residential withplant uptake land use scenario as stipulated in CLR10 and SGV1 (Defra and EnvironmentAgency 2002c,d). The numbers are derived from estimates by the BGS of the proportion ofthe areas and regions that potentially have naturally-occurring elevated levels of arsenic insoils. The data from BGS was constructed on the basis of geostatistics and assumptions.

The response rates ranged from 21.8 per cent to 40.9 per cent for the eight regions, and0 per cent to 66.7 per cent for the 26 areas. One of the assumptions of the survey wasthat the expected response rate would correlate with areas of England and Wales thathave the potential for naturally-occurring elevated arsenic levels. That is authoritieswithin these areas would be more likely to respond to the questionnaire than thoseoutside.

Figure 1 below shows the response rate of participants within the 26 EnvironmentAgency areas plotted against the percentage of the area assumed to have naturally-occurring elevated arsenic levels in soils.


It would be incorrect to analyse this data using linear regression and to calculate a R2

value, as the requirements of linear regression are not met by the data. In particular, therequirement for independent random scatter around the line and normally distributederrors. A better way to deal with proportions data is by using Generalised LinearModelling (GLM). Using this model, the assessor can specify that the 'Y' variable is abinomial response (r responses out of n attempts), rather than assume a conventionalcontinuous variable as required in linear regression (100*r/n). Following a GLM analysis,it was shown that the t value is 2.42, which is statistically significant, single-sided, atP<0.02. The single-sided stance is appropriate and justified, as the direction of theassociation of the data has been stated in advance of the assessment. That is: thegreater the percentage area of a participant’s authority that is covered by naturally-occurring elevated arsenic levels, the more likely the participant was to reply to thequestionnaire.

To summarise, the data in Table 1 and Figure 1 allows us to say with 98 per centconfidence that response rates tended to be higher in areas with elevated arsenic levels.This means that there is likely to be an upward bias in the survey's results for eachquestion.

It is therefore only truly statistically appropriate to view the following results asrepresenting the percentage of those who responded, rather than for England and Walesas a whole.

Table 1 contains the data organised in terms of the Environment Agency's regions andareas. For columns 2 and 3, rows that are not highlighted (the areas) add up to the valuespresented in the row highlighted above them (the regions). Those highlighted values addup to the value presented in the bottom ‘Totals’ row.

The values presented in columns 4 and 5 do not continue this relationship. The values incolumn 5 have been calculated using a GIS (Graphical Information System), on the basisof individual footprints for both areas and regions separately.

Figure 1: Response Rate vs Percentage of Environment Agency Areas with Elevated Arsenic Concentrations

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Table 1 Response rate of questionnaire survey

Environment Agency Regionand Areas

Number ofAuthorities

Number ofResponses

ResponseRate(Percentage)

Percentageof Area >SGV

Anglian Region 52 14 26.9 49Central Area 12 3 25 44Eastern Area 19 4 21 0Northern Area 21 7 38.1 97Midlands Region 64 14 21.9 23Lower Severn Area 11 2 18.2 36Lower Trent Area 25 7 28 51Upper Severn Area 12 3 25 0Upper Trent Area 16 2 12.5 2Northeast Region 42 12 26.2 35Dales Area 15 5 33.3 7Northumbria Area 16 4 18.8 37Ridings Area 11 3 27.3 80North West Region 43 10 23.3 47Central Area 14 1 7.1 0Northern Area 6 2 33.3 95Southern Area 23 7 30.4 4Southern Region 37 11 29.7 0Hampshire & Isle of WightArea

11 5 45.5 0

Sussex Area 12 3 25 0Kent Area 14 3 21.4 0Southwest Region 37 12 32.4 61Cornwall Area 6 3 50 100Devon Area 10 5 50 100North Wessex Area 11 4 36.4 42South Wessex Area 10 0 0 0Thames Region 78 17 21.8 26North East Area 37 11 29.7 24South East Area 30 4 13.3 0West Area 11 2 18.2 43Environment Agency Wales 22 9 40.9 27Northern Area 6 4 66.7 38South East Area 10 2 20 31South West Area 6 3 50 10

Totals 375 99 26.4#

# This figure is calculated as a percentage of all the English and Welsh local authorities(99/375 x 100) and does not relate to the values above it in the column.


Question 1 - In your area/region, do you have any areas where high concentrationsof metals in soils have been identified (i.e. above Soil Guideline Values)?

Repliesticked

Per cent

a) Yes – less than 25% of your area 20 20.2

b) Yes – more than 25% of your area 9 9.1

c) Yes – more than 50% of your area 1 1

d) Yes – more than 75% of your area 4 4

e) Yes – but unsure of area affected 55 55.6

f) No 5 5.1

g) Don’t know 5 5.1

Total number of responses: 99

For question 1, 90 per cent of those who responded reported having sites with highlevels of heavy metal in their areas. Only 5 per cent indicated that such sites had notbeen identified in their area. The final 5 per cent indicated that they did not know whethercontamination existed. Of these, 3 per cent reported that there were grounds forsuspecting that elevated levels of arsenic might exist.

Only 34 per cent of participants knew or were prepared to state an estimate of theproportion of their area that might be affected by heavy metal contamination (by ticking a,b, c or d in question 1 above).

Question 2 - If the answer to question 1 is ‘yes’, please indicate which metals.

Repliesticked

Percent

a) Arsenic 86 96.6

b) Lead 50 56.2

c) Nickel 38 42.7

d) Cadmium 25 28.1

e) Other, please specify below 11 12.4

Total number of responses: 89

Question 2 was answered by 89 of the 99 participants in the survey.The overwhelming majority indicated arsenic as a metal of concern followed by lead,nickel and cadmium.

Participants that ticked ‘Other, please specify below’ in Question 2 identified chromium (4responses), mercury (2), copper (8), zinc (9), manganese (1) and iron (1) as beingelevated within their areas.


Question 3 - What is the source of these metals?

Replyticked

Percent

a) Natural background sources 53 55.8

b) Historical anthropogenic activities, please describe below 51 53.7

c) Don’t know 17 17.9

d) Not applicable 4 4.2

Number of responses: 95

Question 3 was answered by 95 of the 99 participants in this survey. Where the sourcesof contamination were known, natural background and anthropogenic activities wereequally attributed as sources (56 per cent and 54 per cent). However, 18 per cent ofparticipants did not know the source of the contamination.

Of the 54 per cent of participants that ticked answer b to question 3 (attributinganthropogenic activities as sources), just under half of them (23) actually described theactivities in the comments box. These activities can be categorised as:

elevated levels associated with made ground (7 replies); resulting from metal processing (5 replies); mining (7 replies); and various or none attributed industrial processes (15 replies).

Please note that some participants identified more than one anthropogenic activity, asreflected in the numbers in the brackets above.

Figure 3: Question 2: If the answer to question 1 is "yes", please indicate which metals

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Question 4 - Have you had to make regulatory decisions regarding the potentialrisks presented to humans by high metal concentrations in soils?

Repliesticked

Percent

a) Yes – as part of the planning process 84 86.6

b) Yes – as part of the contaminated land regime 36 37.1

c) Yes – as part of another regulatory process, please specify below 6 6.2

d) No 4 4.1

e) Not applicable 0 0


Question 4 was answered by 97 of the 99 participants. The majority of participants (87per cent) had made regulatory decisions under the planning regime with regard to heavymetals in soils.

A smaller percentage (37 per cent) reported that decisions had been made under thecontaminated land regime (Part IIA of the Environmental Protection Act 1990).

This finding is to be expected, as the planning regime is the primary regulatory tool formanaging land contamination in the UK. What came as a surprise was the fact that of the37 per cent (36 participants) that had made decisions under the contaminated landregime, nine reported that they had not made such decisions under the planning regime.

Six per cent of participants stated their authorities had made use of other legislation formaking such decisions. Only half of these identified the legislation used: building controlregulations (2 replies) and legislation dealing with environmental assessment for the saleof council land (1 reply).


Question 5 - If you have had to make regulatory decisions regarding human healthrisks associated with high concentrations of metals in soil, how have you madethese decisions?

Repliesticked

Percent

a) Relied upon Soil Guideline Values published by Defra andthe Environment Agency

76 77.6

b) Relied upon other Generic Assessment Criteria (e.g.ICRCL Threshold trigger concentrations, Dutchtarget/intervention values, consultant derived screeningvalues, etc.), please specify below

40 40.8

c) Relied upon Site Specific Assessment Criteria or SiteSpecific Risk Assessment

69 70.4

d) Other, please specify below 6 6.1

e) Not applicable 4 4.1


All bar one of the participants answered question 5.

Of those that answered, 78 per cent had used SGVs to make regulatory decisions, 41per cent had used other generic assessment criteria and 70 per cent had relied uponsite-specific assessment criteria or a site-specific risk assessment.

The breakdown of the number of participants ticking one, two, three, four or all five of thepossible answers to question 5 is presented in Figure 4 below.

Of the 6 participants relying on other means of making the decisions, they cited criteriasuch as:

• relying on consultant’s statements on bioaccessibility;• and research and scrutiny of original published scientific literature and

consideration of bioavailability testing and interpretation.

F i g u r e 4 : D i s t r i b u t i o n o f M u l t i p l e A n s w e r s t o Q u e s t i o n 5

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Question 6 - If you have received site specific risk assessments of human healthrisks associated with high concentrations of metals in soil (i.e. above SoilGuideline Values), i.e. ticked yes to box 5c, have these assessments includedmeasurements or estimates of oral bioaccessibility?

Repliesticked

Percent

a) Yes – site specific determinations of oral bioaccessibility 47 51.1

b) Yes – estimates of oral bioaccessibility from literature orother sites/locations

13 14.1

c) No 27 29.3



Question 6 was answered by 92 of the 99 participants. Based upon the answers toquestion 5, it would be expected that only 69 participants would answer a, b or c to thisquestion, with the remainder either answering d or not answering the question at all.However, in response to this question, 77 participants indicated that they had receivedsite-specific risk assessments.

Of those who relied upon site-specific assessment criteria or site-specific riskassessments to make their regulatory decisions, 47 indicated that bioaccessibility datahad been included. Responses also showed that 13 participants had received reportscontaining bioaccessibility data that were not site-specific but had been obtained fromliterature or other sites.

The important answers to this question, which are relevant to the issue of bioaccessibilitydata in human health risk assessment, are the number of participants that ticked a and/orb to question 6.

Whilst the table above shows that 47 participants ticked a and 13 ticked b, it is importantto note that nine participants ticked both a and b, whilst four ticked only b and not a.

Of the 99 participants in this survey, 51 of them have received bioaccessibility dataand/or estimates as part of their regulatory duties with respect to land contamination. Itwould be incorrect to state that 60 participants had received such data and/or estimates,because doing so would double count those participants that had received both.

It is concerning to note that a small percentage of participants are receivingbioaccessibility data that is not site-specific.


Question 7 - If you have received measurements or estimates of the oralbioaccessibility of metals, for which metals have you received this information?

Replies ticked Percent

a) Arsenic 49 100

b) Lead 12 24.5

c) Nickel 13 26.5

d) Cadmium 6 12.2



Question 7 was answered by 49 participants. This question invites those who answeredeither a and/or b to question 6 to identify those metals for which they had received suchdata. As such, one would have expected 51 participants to have answered this question.Unfortunately, two participants that had answered either a or b to question 6 did notanswer question 7 and were unavailable to clarify their original answer.

All participants that answered question 7 indicated that they had received oralbioaccessibility data for arsenic. Bioaccessibility data for lead had been received byabout a quarter of respondents (24.5 per cent), with a similar percentage receivingbioaccessibility data for nickel (26.5 per cent).

Data on cadmium bioaccessibility were received by 12 per cent of participants. Oneparticipant had received bioaccessibility data for chromium and one had received data formercury.


Question 8 - In making your regulatory decisions regarding human health risksassociated with high concentrations of metals in soil, have you accepted oralbioaccessibility measurements if they have been undertaken?


a) Yes – whenever provided 20 22.2

b) Yes – sometimes when provided 22 24.4

c) No 6 6.7



Question 8 was answered by 90 of the 99 participants. Based upon the answers toquestion 7, we would have expected 49 to answer a, b or c for question 8.

Of the 49 participants that had received bioaccessibility data (as indicated in question 7),20 replied that they always accepted the results of oral bioaccessibility measurements intheir regulatory decisions, if the measurements have been taken. Twenty-two answeredthat they sometimes accepted them, whilst six answered that they never accepted them.

Forty-two participants stated that the question was not applicable and we assume thismeans that they had not received bioaccessibility data. However, one of thoseparticipants indicated that they had received bioaccessibility data in answer to question7, but went on to state that this question was ‘not applicable’. In the comments, theparticipant added that:

‘I have seen bioaccessibility data for arsenic for two sites. At both of these sitesremediation was still necessary due to the presence of other metal andbenzo(a)pyrene. No bioaccessibility testing was carried out for these substances.If it were the case that a site was affected by high levels of metals and a decisionwas made not to remediate solely on the basis of bioaccessibility testing then Iwould need to give the assessment more consideration and possibly seek outsideadvice.’

Forty-nine participants had received bioaccessibility data as part of their duties relating tothe management of land contamination. Of these, 85.7 per cent had at some timeaccepted oral bioaccessibility data when provided as part of assessments (answered a orb in question 8), and only 12.2 per cent of participants had rejected it (answered c). Oneparticipant did not need to take the bioaccessibility data into account as othercontaminants drove the need to remediate the sites.

Fifty-five per cent of participants that always accept bioaccessibility data (answered a toquestion 8) and 64 per cent of those that sometimes accept bioaccessibility data(answered b to question 8) are based within areas of naturally-occurring elevated arseniclevels. Of the participants that have not accepted bioaccessibility data (answered c toquestion 8), only 33 per cent are based within areas of naturally-occurring elevatedarsenic levels. This was estimated with reference to the areas indicated in Table 1.

From these figures and the breakdown in Table 2, it seems that the existence ofnaturally-occurring elevated levels of arsenic is a driver for participants to acceptbioaccessibility testing.


Table 2 Collated responses to Question 8

Environment Agency Region /Area

Number ofResponses

Percentage ofArea > SGV

AlwaysAcceptResults

SometimesAcceptResults

Have NotAcceptedResults

NotApplicable /did notanswer Qu 8

Anglian Region 14 49 1 6 0 7Central Area 3 44 0 3 0 0Eastern Area 4 0 0 0 0 4Northern Area 7 97 1 3 0 3Midlands Region 14 23 2 1 0 11Lower Severn Area 2 36 1 0 0 1Lower Trent Area 7 51 1 0 0 6Upper Severn Area 3 0 0 0 0 3Upper Trent Area 2 2 0 1 0 1Northeast Region 12 35 2 3 1 6Dales Area 5 7 1 1 0 3Northumbria Area 4 37 1 1 0 2Ridings Area 3 80 0 1 1 1North West Region 10 47 2 3 1 4Central Area 1 0 0 0 0 1Northern Area 2 95 0 0 0 2Southern Area 7 4 2 3 1 1Southern Region 11 0 1 0 0 10Hampshire & Isle of Wight Area 5 0 0 0 0 5Sussex Area 3 0 1 0 0 2Kent Area 3 0 0 0 0 3Southwest Region 12 61 4 5 0 3Cornwall Area 3 100 2 1 0 0Devon Area 5 100 1 1 0 3North Wessex Area 4 42 1 3 0 0South Wessex Area 0 0 0 0 0 0Thames Region 17 26 7 3 3 4North East Area 11 24 3 3 3 2South East Area 4 0 2 0 0 2West Area 2 43 2 0 0 0Environment Agency Wales 9 27 1 1 1 6Northern Area 4 38 0 0 1 3South East Area 2 31 1 0 0 1South West Area 3 10 0 1 0 2

Totals# 99 36 20 22 6 51

# These totals are calculated by summing the ‘region’ rows highlighted in grey; the ‘area’ rows provide a furtherbreakdown of the data in the region rows above them.


Question 9 - If the answer to question 8 is ‘yes’ (ticked boxes 8(a) or 8(b)), forwhich metals have you accepted oral bioaccessibility measurements to supportyour regulatory decisions?

Replies Ticked Percent

a) Arsenic 42 95.5

b) Lead 8 18.2

c) Nickel 6 13.6

d) Cadmium 1 2.3


f) Not applicable 31

Number of responses (not including ‘Not applicable’): 44

Two participants that answered no to question 8 nevertheless answered question 9stating arsenic. Again, as with question 8, this inconsistency could not be resolved.

Of the participants that have accepted bioaccessibility data, all bar two had acceptedarsenic data. In a few cases, lead or nickel bioaccessibility assessments had also beenaccepted (19 per cent and 14 per cent respectively). Although cadmium bioaccessibilitydata had been submitted to six participants (see Question 7), it had only been acceptedby one of them.

Question 10 - If the answer to question 8 is ‘yes’ (ticked boxes 8(a) or 8(b)), whatjustification have you been provided with to support the use of thesemeasurements or estimates?


a) Literature values provided only 3 7.0

b) Laboratory measurements provided only 27 62.8

c) Literature measurements supported by laboratory valuesprovided

14 32.6

d) Additional justification provided, please specify below 6 14.0

e) Not applicable 30


Seventy-three participants answered question 10, but 30 of these stated that thequestion was not applicable. The percentages shown in the table above and text belowhave been calculated on the basis of the 43 participants who ticked a, b, c and/or d.

Only three participants (7 per cent) indicated that risk assessments had been acceptedwithout measurements from the site concerned.

Some of the additional justifications given (ticked d to question 10) are detailed below.


‘In respect of an allotments site we were looking at we also looked at crop sampleswhich adjusted the arsenic value due to the concentration factor.’

‘Site history, geology, mineral species etc.’ ‘We have used bioaccessibility alongside vegetable uptakes and TDI [Tolerable Daily

Intake] calculations. We have also consulted with the HPA [Health Protection Agency]and FSA [Food Standards Agency].’

‘Laboratory measurements provided and the results incorporated into site-specificassessment criteria derived using the SNIFFER [Scottish and Northern Irish Forumfor Environmental Research] risk assessment model.’


Question 11 - If the answer to question 8 is ‘no’ (ticked box 8(c)), on what groundsdid you decide the bioaccessibility measurements or estimates were notacceptable?


a) Measurements were not site specific 4 23.5

b) Insufficient number of measurements 4 23.5

c) Insufficient validation of measurements 4 23.5

d) Inadequate interpretation of measurements 5 29.4

e) No guidance from the EA is available to acceptbioaccessibility in risk assessments

10 58.8

f) Other, please specify below 6 35.2

g) Not applicable 43


Whilst question 11 was designed to elicit responses from those six participants who hadticked answer 8(c), eleven participants who had ticked 8(b) also answered this question.This was because answer 8(b) stated that participants sometimes acceptedbioaccessibility data and hence, by implication, sometimes rejected it.

The principal reason cited by 10 participants (61 per cent) for rejecting bioaccessibilityassessments was a lack of guidance from the Environment Agency. Four furtherparticipants commented (to question 11 or to other questions) that they would not acceptbioaccessibility data in future without further guidance. Nine participants (56 per cent)had found assessments at fault and ticked one or more of answers a to d (a lack of site-specific measurements, insufficient number or validation of measurements, orinadequate interpretation).

The other reasons for finding assessments unacceptable included:• a complete absence of robust statistical treatment of data – ‘magic number’

approach;• an over-reliance on professional judgement;• bioaccessibility analyses were without UKAS (UK Accreditation Service) or

MCerts accreditation.


Questions 12 - For sites where metals are contaminants of concern, howfrequently have you received measurements or estimates of oral bioaccessibilityof metals in the last two years?


a) Never 34 41.4

b) Occasionally (<25% of sites assessed) 39 47.5

c) Regularly (>25% of sites assessed) 6 7.3

d) Most of the time (>50% of sites assessed) 0 0

e) Nearly always (>75% of sites assessed) 3 3.7

f) Not applicable 9


Question 13 - Have you noticed an increase in the application of measurements orestimates of oral bioaccessibility of metals in the last two years?


a) No 36 50.7

b) Yes – a slight increase 18 25.4

c) Yes – a reasonable increase (e.g. twice as often as twoyears ago)

11 15.5

d) Yes – a large increase (e.g. more than twice as often astwo years ago)

6 8.5

e) Not applicable 14


In response to question 12, for sites where metals are contaminants of concern, mostparticipants had only occasionally (<25 per cent) received measurements or estimates oforal bioaccessibility in the past two years. In response to question 13, about half ofparticipants reported that the use of bioaccessibility testing was increasing.

With respect to question 12, only three participants received bioaccessibility data formore than 50 per cent of sites (although all three had actually received bioaccessibilitydata for more than 75 per cent of sites). In all three cases, this is a recent phenomenon;the participants’ responses to question 13 indicated a large increase in the use ofbioaccessibility data over the past two years. These participants are based in areas withhigh proportions of natural levels of arsenic and other heavy metals.


Comments (Question 14)

Question 14 invited comments on the participants' experiences of or opinions on theapplication of bioaccessibility measurements to land contamination issues; 28 of themprovided comments. The answers have been reviewed and grouped into some broadthemes.

In the context of the contaminated land regime

The most detailed responses discussed bioaccessibility testing not as a scientific issue,but as a practical and policy element of the contaminated land regime. These participantsbelieve that most of their land area would be judged as contaminated land, if existingSGVs were applied. This indicates some uncertainty over the role of generic assessmentcriteria in the management of land contamination and, in particular, in the contaminatedland regime.

The following extract is an example of a typical response from the participants:

‘The Borough has an elevated level of naturally occurring arsenic which regularlyexceeds the arsenic SGV. In order to allow development, the Council hasaccepted bioavailability data. This is on the basis that (a) it is impractical toremediate all the affected land in the Borough, (b) the bioavailability tests thathave been carried out show that the bioavailable levels are usually below theSGV and (c) this is in line with the risk assessment approach of CLEA[Contaminated Land Exposure Assessment].’

Inadequate basis for decision making

As indicated above, many participants commented upon a lack of scientific information orguidance in relation to bioaccessibility of heavy metals and called for a standardised,validated test method. The following description of a validation process from a BoroughCouncil is broadly typical:

‘Only received once. Accepted results as were based on PBET [PhysiologicallyBased Extraction Test] analysis. Felt that this was the way to go, given: theSNIFFER model provides for a percentage of bioavailability of the contaminant;the fact that CLEA still has not provided a site-specific model; that SGV valuesare based on 100 per cent bioavailability. I rung up BGS and spoke to the chapwho did the PBET tests and asked if the Environment Agency accepted it, heresponded that all did except the Yorkshire area. Read up about PBET on theInternet and ultimately came to the conclusion to accept the values on this site.’

Some participants felt that the problem was inherently intractable, one stated:

‘Some consultants have proposed using bioaccessibility and I have alwaysrefused to accept it. The problem is that you cannot mimic in a test tube whathappens in terms of fate in the environment (open system)… Ultimately thequestion is whether contaminant X at concentration Y is likely to affect receptorZ.’

Poor use of bioaccessibility in risk assessment and risk management

The participants’ comments clearly place an onus on consultants to conductbioaccessibility assessments at a higher standard of competence than currently seems to


be the case. This is demonstrated by the answers to question 11 above. In one extremecase, a participant stated that:

‘The consultant didn’t even know about the existence of CLEA (Defra and EnvironmentAgency 2002c) or the withdrawal of ICRCL [Interdepartmental Committee on theRedevelopment of Contaminated Land] (Defra 2002)’.

The participants consistently identified several failings in risk management reports thathad been submitted to them. It is evident that the bioaccessibility approach, which wouldotherwise be accepted by many councils, is being rejected because:

• not enough samples are being taken from the site;• the approach is being applied blindly without an understanding of the science behind

it;• inappropriate literature information is being cited in support;• and the risk assessments are not being carried out correctly.

One Borough Council stated that ‘magic number’ approaches featuring a ‘completeabsence of robust statistical treatment of data’ have been undertaken.

Whilst oral bioaccessibility measurements of heavy metals can only be applied to the soilingestion pathways of human health risk assessment models, it is clear that consultantshave, in some cases, not made this distinction.

‘In the early days it was common for consultants to apply the bioaccessibility factor to allroutes of exposure,’ remarked one participant.


4 DiscussionThe objectives of the questionnaire survey were to capture the experiences and views ofthose responsible for regulating land contamination, with particular reference to in vitrobioaccessibility testing in risk assessments. Under the existing legislative framework,issues of land contamination fall largely within the remit of local authorities. Thereforelocal and unitary authorities were contacted as part of this project. Out of 375 potentialparticipants identified, 298 were contacted, of which 99 responded to the questionnairesurvey.

In general, the questions elicited a wide range of views and comments from those thatparticipated in the survey. The responses received were useful because they helped toidentify the issues that need to be addressed by regulators, industries and researchorganisations in a future bioaccessibility work programme for England and Wales.

Elevated arsenic levels appear to be a major land contamination issue in large areas ofEngland and Wales, with lead, nickel and cadmium also reported as potential issues. Thesource of elevated arsenic in soils is perceived by participants of the survey to be eithernatural (geogenic) or a legacy of historic mining operations.

In vitro bioaccessibility testing is used as part of site-specific risk assessments. Theparticipants had different views regarding bioaccessibility and there appears to be a lackof a consistent approach, policy or stance across England and Wales. A number of localauthorities used bioaccessibility data to assist their decision-making processes. Arsenicwas the main contaminant assessed using in vitro bioaccessibility test methods.However, the survey revealed that these in vitro methods are also being used for othercontaminants. There were circumstances where bioaccessibility data were either notapplicable for or accepted in the decision-making process.

From the responses to the questionnaire (with only a couple of exceptions), it was notclear whether any rationale was used to evaluate scientifically the bioaccessibility testmethod or the use of bioaccessibility data in risk assessment. It was also not clearwhether scientific evidence has been provided to support the correlation between in vitrobioaccessibility data and in vivo bioavailability data. There were reports of theextrapolation of data from different locations and from literature values in making site-specific decisions.

In vitro testing is considered to be substance-, form- and soil-specific. However, it alsoappeared possible that in some instances the same test methods were used regardlessof contaminant or soil properties. It was not clear whether the participants recommendeda standard protocol for use in sampling, in vitro test method application, data reportingand data use as part of the decision-making process. This raises the question of whetherusers understand the validity, reproducibility and robustness of the in vitrobioaccessibility test methods that are currently available in the UK and elsewhere(Environment Agency 2005 a,b).

The survey also indicated that the use of in vitro bioaccessibility test methods as part ofsite-specific risk assessments is increasing.

Some participants indicated that guidance from the Environment Agency would changetheir position on the acceptability of in vitro bioaccessibility testing in site-specific riskassessment. Based on a review of the current science, the Environment Agency's view is


that it cannot recommend the routine use of bioaccessibility testing in risk assessment(Environment Agency 2005a). The view of the Environment Agency is reflected byregulators in North America and Europe, where in vitro bioaccessibility test methodshave not yet received regulatory acceptance for use in human health risk assessment. Invitro bioaccessibility is a useful concept, but in terms of acceptance as a routine tool inrisk assessment for most contaminants, including arsenic, it is still an area where furtherresearch is needed (Schoof 2004, Environment Agency 2005a,b, USEPA 2005, Saikat2006).

Nevertheless, this survey demonstrates that bioaccessibility tests have been received byroughly 50 per cent of participants, and that 85.7 per cent of those have accepted themin making regulatory decisions.

There appears to be a need for detailed guidance on all aspects of the use of in vitrobioaccessibility approaches for the risk assessment of land contamination. Suchguidance should be centred on validated substance-specific in vitro test protocols. Itshould contain information on the applicability of in vitro test methods, sitecharacterisation and sampling design. It should clearly state the need to quantify anyuncertainty inherent within the protocols, and provide guidance on presenting data andthe use of data in the risk assessment process.


5 SummaryThe main findings of this survey are detailed below.

• Ninety per cent of participants reported having sites with high levels of heavy metalsin their areas.

• The overwhelming majority of participants indicated arsenic as the main metal ofconcern, followed by lead, nickel and cadmium.

• The source of metal contamination was attributed equally to natural backgroundsources and anthropogenic activities.

• Most of the participants had made regulatory decisions under the planning regimewith regard to heavy metals in soils. A smaller percentage (roughly a third) reported thatdecisions had been made under the contaminated land regime (Part IIA of theEnvironmental Protection Act 1990).

• Of the 99 participants in this survey, half of them had received bioaccessibility dataand/or estimates as part of their regulatory duties with respect to land contamination. Allthe participants that had received such data had received it for arsenic. In addition,bioaccessibility data for lead and nickel had been received by about a quarter of theparticipants.

• Of those that had received bioaccessibility data as part of risk assessments, the vastmajority had at some time accepted it. Arsenic is the main contaminant for whichparticipants evaluated bioaccessibility data.

• Those rejecting bioaccessibility data did so either on the basis of a lack of centralisedguidance on its use or due to poor use of the data within the risk assessments.

• Most participants had only occasionally received measurements or estimates of oralbioaccessibility in the past two years, but about half reported that the use ofbioaccessibility testing was increasing.

In parallel to this questionnaire survey, the Environment Agency has been conducting aring test on current in vitro bioaccessibility laboratory methods being used in the UK. Thiswill help our understanding of some of the key uncertainties (such as reproducibility) thatare currently not made explicit when using, or reviewing the use of, such data in humanhealth risk assessments. However, the absence of in vivo data for the samples used inthe ring test study will not allow an assessment to be made of the reliability androbustness of in vitro bioaccessibility methods.


ReferencesDefra, 2002. Contaminated land advice note number 1/02: withdrawal of ICRCL guidancenote 59/83. Available from:http://www.defra.gov.uk/environment/land/contaminated/pdf/clan1-02.pdf

Defra, 2005. Contaminated land advice note number 2/05: soil guideline values and thedetermination of land as contaminated land under Part IIA. Available from:http://www.defra.gov.uk/environment/land/contaminated/pdf/Clan2-05-SGVs.pdf

Defra and the Environment Agency, 2002a. Overview of the development of soilguideline values and related research. (R&D Technical Report CLR 7.)

Defra and the Environment Agency, 2002b. Contaminants in soils: collation oftoxicological data and intake values for humans: consolidated main report. (R&DTechnical Report CLR 9.)

Defra and the Environment Agency, 2002c. The contaminated land exposureassessment model (CLEA): technical basis and algorithms. (R&D Technical Report CLR10.)

Defra and the Environment Agency, 2002d. Guideline values for contaminants in soils:SGV series. (R&D Technical Report SGV 1: Arsenic.)

DETR, 2000. The Contaminated Land Regulations. (SI 2000/227.)

Environment Agency, 2005a. Environment Agency's science update on the use ofbioaccessibility testing in risk assessment of land contamination. Available from:http://www.environment-agency.gov.uk/commondata/acrobat/science_update_1284046.pdf

Environment Agency, 2005b. Report of the Environment Agency's Workshop on PotentialUse of Bioaccessibility Testing in Risk Assessment of Land Contamination. Availablefrom: http://publications.environment-agency.gov.uk/epages/eapublications.storefront/444cc569017fabb8273fc0a8029606eb/Product/View/SCHO1005BJSQ&2DE&2DE)

Environment Agency and the British Geological Survey, 2002a. In-vitro methods for themeasurement of the oral bioaccessibility of selected metals and metalloids in soils: acritical review. (R&D Technical Report P5-062/TR/01.)

Environment Agency and the British Geological Survey, 2002b. Measurement of thebioaccessibility of arsenic in UK soils. (R&D Technical Report P5-062/TR01.)

ODPM, 2004. Planning policy statement 23: planning and pollution control. Availablefrom: http://www.odpm.gov.uk/index.asp?id=1143916

Saikat, S., 2006. Bioavailability/bioaccessibility testing in risk assessment of landcontamination: a short review. Chemical Hazards and Poisons Report, Issue 6, February2006, 44–47. Available from:http://www.hpa.org.uk/chemicals/reports/chapr6_feb2006.pdf

http://www.defra.gov.uk/environment/land/contaminated/pdf/clan1-02.pdf

http://www.defra.gov.uk/environment/land/contaminated/pdf/Clan2-05-SGVs.pdf

http://www.environmentagency.gov.uk/commondata/acrobat/science_update_1284046.pdf

http://publications.environmentagency.gov.uk/epages/eapublications.storefront/444cc569017fabb8273fc0a8029606eb/P

http://www.odpm.gov.uk/index.asp?id=1143916

http://www.hpa.org.uk/chemicals/reports/chapr6_feb2006.pdf


Scoof, R.A., 2004. Bioavailability of soil-borne chemicals: method development andvalidation. Human and Ecological Risk Assessment, 10(4), 637–646.

US EPA, 2005. Estimation of relative bioavailability of lead in soil and soil-like materialsusing in-vivo and in-vitro methods. Washington DC: Office of Solid Waste andEmergency Response, US EPA.

WAG, 2001. The Contaminated Land (Wales) Regulations 2001. The Welsh AssemblyGovernment/HMSO, (Statutory Instrument No. 2197 (W.157)).


Appendix AQuestionnaire for Local Authority Officers

Name:

Position:

Organisation:

Address:

TelephoneNumber:

Facsimile Number:

E-mail Address:

Please tick as many answers as appropriate:

1) In your area / region, do you have any areas where high concentrations of metalsin soils have been identified (i.e. above Soil Guideline Values)?

a) Yes – less than 25% of your area

b) Yes – more than 25% of your area

c) Yes – more than 50% of your area

d) Yes – more than 75% of your area

e) Yes – but unsure of area affected

f) No

g) Don’t know

Comments:

2) If the answer to question 1 is ‘yes’, please indicate which metals.

a) Arsenic

b) Lead

c) Nickel

d) Cadmium

e) Other, please specify below

Comments:


3) What is the source of these metals?

a) Natural background sources

b) Historical anthropogenic activities, please describe below

c) Don’t know

d) Not applicable

Comments:

4) Have you had to make regulatory decisions regarding the potential risks presentedto humans by high metal concentrations in soils?

a) Yes – as part of the planning process

b) Yes – as part of the contaminated land regime

c) Yes – as part of another regulatory process, please specify below

d) No

e) Not applicable

Comments:

5) If you have had to make regulatory decisions regarding human health risksassociated with high concentrations of metals in soil, how have you made thesedecisions?

a) Relied upon Soil Guideline Values published by Defra and theEnvironment Agency

b) Relied upon other Generic Assessment Criteria (e.g. ICRCL Thresholdtrigger concentrations, Dutch target/intervention values, consultantderived screening values, etc.), please specify below

c) Relied upon Site Specific Assessment Criteria or Site Specific RiskAssessment

d) Other, please specify below

e) Not applicable

Comments:


6) If you have received site specific risk assessments of human health risksassociated with high concentrations of metals in soil (i.e. above Soil GuidelineValues), i.e. ticked yes to box 5c, have these assessments includedmeasurements or estimates of oral bioaccessibility?

a) Yes – site specific determinations of oral bioaccessibility

b) Yes – estimates of oral bioaccessibility from literature or othersites/locations

c) No

d) Not applicable

Comments:

7) If you have received measurements or estimates of the oral bioaccessibility ofmetals, for which metals have you received this information?

a) Arsenic

b) Lead

c) Nickel

d) Cadmium


Comments:

8) In making your regulatory decisions regarding human health risks associated withhigh concentrations of metals in soil, have you accepted oral bioaccessibilitymeasurements if they have been undertaken?

a) Yes – whenever provided

b) Yes – sometimes when provided

c) No

d) Not applicable

Comments:


9) If the answer to question 8 is ‘yes’ (ticked boxes 8(a) or 8(b)), for which metalshave you accepted oral bioaccessibility measurements to support your regulatorydecisions?

a) Arsenic

b) Lead

c) Nickel

d) Cadmium


f) Not applicable

Comments:

10) If the answer to question 8 is ‘yes’ (ticked boxes 8(a) or 8(b)), what justificationhave you been provided with to support the use of these measurements orestimates?

a) Literature values provided only

b) Laboratory measurements provided only

c) Literature measurements supported by laboratory values provided

d) Additional justification provided, please specify below

e) Not applicable

Comments:

11) If the answer to question 8 is ‘no’ (ticked box 8(c)), on what grounds did youdecide the bioaccessibility measurements or estimates were not acceptable?

a) Measurements were not site specific

b) Insufficient number of measurements

c) Insufficient validation of measurements

d) Inadequate interpretation of measurements

e) No guidance from the EA is available to accept bioaccessibility in riskassessments

f) Other, please specify below

g) Not applicable

Comments:


12) For sites where metals are contaminants of concern, how frequently have youreceived measurements or estimates of oral bioaccessibility of metals in the lasttwo years?

a) Never

b) Occasionally (<25% of sites assessed)

c) Regularly (>25% of sites assessed)

d) Most of the time (>50% of sites assessed)

e) Nearly always (>75% of sites assessed)

f) Not applicable

Comments:

13) Have you noticed an increase in the application of measurements or estimates oforal bioaccessibility of metals in the last two years?

a) No

b) Yes – a slight increase

c) Yes – a reasonable increase (e.g. twice as often as two years ago)

d) Yes – a large increase (e.g. more than twice as often as two yearsago)

e) Not applicable

Comments:

14) If you have any additional information that you wish to provide on your experiencesor opinions of the application of bioaccessibility measurements to landcontamination issues please detail below.


15) Would you be happy for us to contact you to discuss your answers further?

a) Yes, by telephone

b) Yes, by e-mail

c) Yes, by post

d) No

Comments:

Science project SC040060 - Questionnaire survey on the use of In-vitro bioaccessibility in human health risk assessment40

Appendix BTable B.1 Summary of answers and calculated 90% confidence intervals

90% conf. intervalResponse

No ofrespondents

Total no ofresponses

% ofrespondents Lower Upper

Question 1 99Yes < 25% 20 20.2 14.7 26.9Yes > 25% 9 9.1 5.4 14.4Yes > 50% 1 1.0 0.2 4.2Yes >75% 4 4.0 1.8 8.3Yes Unsure of area affected 55 55.6 48.0 62.9No 5 5.1 2.4 9.6Don't know 5 5.1 2.4 9.6Question 2 89Arsenic 86 96.6 92.2 98.8Lead 50 56.2 48.1 64.0Nickel 38 42.7 34.9 50.8Cadmium 25 28.1 21.3 35.8Chromium 4 4.5 1.9 9.3Mercury 2 2.2 0.6 6.3Copper 8 9.0 5.1 14.8Zinc 9 10.1 6.0 16.1Manganese 1 1.1 0.2 4.7Iron 1 1.1 0.2 4.7Other 11 12.4 7.8 18.7

Question 3 95


Natural background sources 53 55.8 48.1 63.3Historical anthropogenic activities 51 53.7 46.0 61.2Don't know 17 17.9 12.6 24.6Not applicable 4 4.2 1.8 8.7Question 4 97Yes as part of the planning process 84 86.6 80.5 91.2Yes as part of the contaminated land regime 36 37.1 30.1 44.7Yes as part of another regulatory process 6 6.2 3.2 11.1No 4 4.1 1.8 8.5Not applicable 0 0.0 0.0 2.6Question 5 98Relied upon Soil Guideline Values published by Defra & theEA

76 77.6 70.6 83.3

Relied upon other Generic Assessment Criteria 40 40.8 33.6 48.4Relied upon Site Specific Assessment Criteria or Site SpecificRisk Assessment.

69 70.4 63.1 76.9

Other 6 6.1 3.2 10.9Not applicable 4 4.1 1.8 8.4Question 6 92Yes – using site specific determinations of oral bioaccessibility 47 51.1 43.2 58.9Yes – using determinations of oral bioaccessibility fromelsewhere

13 14.1 9.3 20.5

No 27 29.3 22.6 37.0Not applicable 15 16.3 11.1 23.0

Question 7 49Arsenic 49 100.0 94.5 100.0Lead 12 24.5 15.4 35.8Nickel 13 26.5 17.1 38.0Cadmium 6 12.2 5.9 22.0


Other 2 4.1 1.0 11.7Question 8 90Yes – whenever provided 20 22.2 16.1 29.6Yes – sometimes when provided 22 24.4 18.1 31.9No 6 6.7 3.4 12.0Not applicable 42 46.7 38.8 54.7Question 9 75Arsenic 42 56.0 46.9 64.7Lead 8 10.7 6.0 17.6Nickel 6 8.0 4.0 14.4Cadmium 1 1.3 0.2 5.7Other (not specified) 1 1.3 0.2 5.7Not applicable 31 41.3 32.7 50.4Question 10 73Literature values provided only 3 4.1 1.4 9.6Laboratory measurements provided only 27 37.0 28.5 46.2Literature measurements supported by laboratory valuesprovided

14 19.2 12.7 27.4

Additional justification provided, please specify below 6 8.2 4.1 14.8Not applicable 30 41.1 32.4 50.3

Question 11 60Measurements were not site specific 4 6.7 2.7 13.9Insufficient number of measurements 4 6.7 2.7 13.9Insufficient validation of measurements 4 6.7 2.7 13.9Inadequate interpretation of measurements 5 8.3 3.8 16.0No guidance from the EA is available to acceptbioaccessibility

10 16.7 9.9 25.8

Other 6 10.0 4.9 18.1


Not applicable 43 71.7 61.5 80.3Question 12 90Never 34 37.8 30.3 45.8Occasionally (<25% of sites assessed) 39 43.3 35.6 51.4Regularly (>25% of sites assessed) 6 6.7 3.4 12.0Most of the time (>50% of sites assessed) 0 0.0 0.0 2.9Nearly always (>75% of sites assessed) 3 3.3 1.2 7.7Not applicable 9 10.0 5.9 15.9Question 13 85No 36 42.4 34.4 50.7Yes – a slight increase 18 21.2 15.0 28.7Yes – a reasonable increase (e.g. twice as often as two yrsago)

11 12.9 8.1 19.6

Yes – a large increase (e.g. > twice as often as two yrs ago) 6 7.1 3.6 12.7Not applicable 14 16.5 11.0 23.6

Science project SC040060 - Questionnaire survey on the use of In-vitro bioaccessibility inhuman health risk assessment 44

Table B.2 Breakdown of Multiple Reponses to Each Question

No of responses Q1 Q2 Q3 Q4 Q5 Q6 Q70 0 10 4 2 1 7 501 99 30 66 67 30 83 292 0 21 28 27 42 8 133 0 16 1 3 23 1 24 0 12 0 0 3 0 45 0 2 0 0 16 0 37 0 18 49 010 011 0

Total no of respondents 99 89 95 97 98 92 49Total no of responses 99 235 125 130 195 102 82No of multipleresponses

0 146 30 33 97 10 33

Responses perrespondent

1.00 2.64 1.32 1.34 1.99 1.11 1.67

No of responses Q8 Q9 Q10 Q11 Q12 Q130 9 24 26 39 9 141 90 63 66 51 89 852 0 11 7 4 1 03 0 0 0 3 0 04 0 1 0 2 0 05 0 0 0 0 06 0 0 07 0

Total no ofrespondents

90 75 73 60 90 85

Total no of responses 90 89 80 76 91 85No of multipleresponses

0 14 7 16 1 0

Responses perrespondent

1.00 1.19 1.10 1.27 1.01 1.00

Note: Each question has a different number of possible answers that participantscould have ticked and each question is cut off with regard to the number ofresponses up to the maximum possible (for example, question 8 has four differentpossible answers and question 11 has seven).

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